Electric lamp.



PATENTED NOV. 21, 1905.

E. THOMSON.

ELECTRIC LAMP.

APPLICATION FILED MAY8,1899.

Inventor.

Elihu Thomson, WW

I flb'cy.

Witnesses.

mm 1+ mag Q fLZ/ UNITED STATES PATENT OFFICE.

ELIHU THOMSON, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC LAMP.

Specification of Letters Patent.

Patented Nov. 21, 1905.

Application filed May 8, 1899. Serial No. 715,932.

To ctlZ whom it may concern:

Be it known that I, ELIHU THoMsoN, a citizen of the United States, residing at Swampscott, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Electric Lamps, of which the following is a specification.

My invention consists in an improvement in that class of lamps in which the light-giving conductor is a pyro-electrolyte or is of such a nature that it is of low actual or apparent conductivity at ordinary temperatures and of suflficient conductivity to carry substantial current at higher temperatures, particularly at the temperature of luminescence. Such lamps have been known for a considerable time, but very considerable difliculties have been encountered in causing them to start without the application of an external flame and without unduly complex mechanism. My present improvements aim to overcome this difliculty and to provide a lamp of the class described which shall be self-starting, reliable, and efiicient.

In the drawings annexed to this specification, Figure 1 represents a sectional elevation of a lamp constructed in accordance with my present invention, while Fig. 2 is an end elevation of the same lamp. Fig. 3 is a modification, and Fig. 4 is a diagram of the circuit connections.

Referring more particularly to Figs. 1 and 2, A is the base or cap, preferably constructed of metal and provided with a ring B for attachment to a hook or other suitable support. C is a globe, of glass or other transparent or translucent material, which is screwed into the base A, as shown in Fig. 1. A washer of felt or other suitable material is preferably interposed, as shown at D. The light-giving body or glower E consists of a cylinder of porcelain or some other substance of the class above described. As examples of the substances which may be used in this connection, I may mention magnesia or otheroxids of the alkaline-earth metals or mixtures of such oxids. The cylinder E is provided with points E at each end, which points are carried by the screws F F, which are preferably formed of platinum or some other highly infusible material. These screws are adjusted by checknuts F F in supports Cr G, which are formed of conducting metal and are fastened by screws to an insulating-base H, which in turn is supported from the cover A. Suitable terminals K K are provided for attachment to the wires of the circuits. Two carbon-blocks or pencils L L are attached by metal clips 01' supports to the two supporting-arms G G, and a third block of carbon L is fastened to a laminated-iron core M. This core works with a dash-pot effect in the interior of a coil of wire N, and a spring O serves to hold the block L in the position shown in the drawings/except when current is flowing. A coil P is so placed as to furnish when current flows through it a field of force acting upon the gap between the two pencils L L. The current, supposed to enter at the terminal K, flows down the left-hand support G and through the pencils L L L and the block E in multiple to the right-hand support G, as shown in Fig. 4:. Thence it flows through the blow-out coil P and the solenoid N in series to the terminal K.

The action of the lamp above described is as follows: When current is first admitted, the block E is cold, so that no substantial'amount of current can flow therethrough, which results in causing substantially all of the current to pass through the blocks L L L. At the same time the solenoid N is energized, and the block L is gradually lifted against the ac tion of the spring O. The dash-pot action prevents this lifting from taking place too suddenly. This tends to cause the arc to form between the points L L or from the block L to the block L and from the block L to the right-hand block L. The field of force generated by the coil P is in such .a direction as to tend to cause this are to pass down and to play upon the block E, substantially enveloping the same in a mass of highly-heated arcvapors. When the block L has reached its final position, this are will either break or be confined to the carbon blocks LL. Soon after the current is admitted the light-giving body E will be heated to a point where it will take a considerable amount of current, which will still further increase the power of the coil P, so that the are between the points L L will be extinguished if it has not already been extinguished by the movement of the block L. The lamp will now continue to run without interruption, unless for some reason the current-supply is interrupted. If this occurs, the

block L will again assume the position shown in the drawings, and the starting action will be repeated. It will be noticed that the arcingpoints L L L are formed of carbon or some other suitable material and are placed in spring-clips T T T in such a way that the arcing-points maybe taken out and renewed when they are partially consumed.

A modified form of myinvention is shown in Fig. 3. In this figure the connections are the same, except that the block L and the starting-coil N are omitted, and in place thereof is substituted a thermostatic device, which, as here shown, consists of two strips of metal Q, R of different coefiicients of expansion, fastened by insulating-supports to the two supporting-arms G G, which carry the blocks L L. These supporting-arms are in this case pivoted at the points G G and the coil P is, as before, connected in series with the whole lamp. The action of this form will be readily understood. hen current is first admitted, the two blocks LL are supposed to be in loose contact, such as to permit a considerable amount of current-[low ii the lamp is on a constant-potential circuit. The result would be to heat the thermostatic device Q, R sufficiently to cause the pivoted arms (ur G to be slightly separated from each other, forming an are. This are would be directed by the coil P upon the light-giving body E until broken by the wide separation of the points LL. 11 now the temperature of the lamp should fall slightly on account of the extinction-of the are, the carbon blocks would still remain separated, though perhaps not by so great a distance; but if the lamp should actually go out it would soon cool to such a point that the blocks L L would again make contact and establish an are, as before.

In general I prefer to permit access of air to the lamp, and this I may accomplish by openings S S, as shown in Figs. 1 and 2.

By the term pyro-electrolytic conductor as used in this specification and in the claims I mean to imply any conductor whatever which is of very high resistance at ordinary temperatures and of sufliciently low resistance at higher temperatures to permit the passage of current to raise and maintain it incandescent.

It will be evident that the lamp above described may be varied to a considerableextent without departing from the spirit and scope of my invention and that it may be used either on series circuits or multiple-arc circuits; but it is preferably used on multiplearc circuits. Further, it will be evident that in some of its aspects my invention is applicable to any type of lamp which requires to be started, whether the conducting-body be a pyro-electrolyte or not.

W hat 1 claim as new, and desire to secure by Letters Patent of the United States, is-

1. The combination in an electric lamp, of a pyro-electrolytic conductor in an electric circuit,arcing-points in proximity thereto, means for establishing an arc forgiving initial heat to the conductor, and means for breaking the are when the conductor attains the proper temperature.

2. The combination in'an electric lamp, of a pyro-electrolytic conductor, means for establishing an arc in proximity thereto, and means for directing the are upon the conductor.

3. The combination with a pyro-electrolytic conductor, of arcing-points in multiple therewith, means for separating said arcing-points, and means for directing the arc between said points upon the electrolytic conductor.

4;. The combination with apyro-electrolytic conductor, of means for forming an arc in proximity thereto, and means for creating a magnetic field adapted to direct the said are upon said conductor.

5. The combination in an electric lamp, of arcing-points and a pyro-electrolytic conductor in multiple, and a coil in series therewith for directing the are from said arcing-points upon said conductor.

6. The combination in an electric lamp, of arcing-points and a pyro-electrolytic conductor in multiple, a coil in series therewith for directing the are from said arcing-points upon said conductor, and means for separating said arcing-points when the conductor attains the proper temperature.

7. In an electric lamp, the combination with a pyro-electrolytic conductor connected or adapted to be connected in an electric circuit, of arcing-points for heating said conductor, and means for automatically separating said points to such an extent that the extinguishment of the are is assured.

8. The combination in an electrielamp, with a m-electrolytic conductor connected or adapted to be connected in an electric circuit, of arcing-points for heating said conductor, and a device for automatically causing a cessation of said heating efie-ct when the conductor has been heated.

9. The combination with a normally nonself-starting electric-light-giving body, of arcing-points in proximity thereto for causing or assisting the starting action, and means for directing the are from said points upon the light-giving body.

10. The combination with a pyro-electrolyticilluminantin an electric circuit, of means for establishing an arc in proximity thereto, and means for establishing a magnetic field which deflects the are toward the pyro-eleetrolyte and increases in intensity as the latter becomes more conducting, to eventually blow out the are.

1 1. The combination with a pyro-electrolytic illuminant in an electric circuit, of means for establishing an arc in proximity thereto, and means for deflecting the arc toward the pyroelectrolyte, which means increases in intensity as the latter becomes more conducting, to eventually blow out the are.

12. The combination with a pyro-electrolyte in an electric circuit, of arcing=points in proximity thereto, means for separating said arc ing-points to rupture the arc, and means for establishing a magnetic field which cooperates with said means for separating the arcing-points, in order to insure the extinguishment of the arc.

13. The combination with a pyro-electrolyte in an electric circuit, of means for establishing a voltaic arc in proximity to said pyroelectrolyte, and means adapted to automatically rupture the are when the pyro-electrolyte is sufficiently heated.

14. In an electric lamp, the combination with a pyro-electrolyticconductor connected or adapted to be connected in an electric circuit, of arcing-points connected in parallel with said conductor, and a solenoid connected in series with the points for separating them to establish an are for heating the conductor, said solenoid being in series with the conductor, whereby as the resistance of the latter decreases as its temperature increases, while the resistance of the path of the arcing-points is increasing, additional current will-be supplied to the solenoid to separate the points to such an extent that the arc is broken.

15. In an electric lamp, the combination with a pyro-electrolytic conductor connected or adapted to be connected in an electric circuit, of arcing-points adapted to heat said conductor, a solenoid connected in series with the conductor and acting to separate the arcingpoints, whereby as the resistance of the latter decreases as its temperature increases, additional current will be supplied to the solenoid to separate the points to such an extent that the arc is broken.

16. The com bination with a pyro-electrolytic illuminant in an electric circuit, of arcingpoints in proximity thereto, and means for gradually separating said points to form an are for heating said pyro-electrolyte and eventually rupturing the are thus formed, when the pyro-electrolyte is sufficiently heated.

17. In an electric lamp, the combination with a pyro-electrolytic conductor connected or adapted to be connected in an electric circuit, of arcing-points, and means regulated by the degree of current flowing through the pyro-electrolyte, for separating said points to such an extent when the conductor has become heated that the arc is extinguished.

18. In an electric lamp, the combination with a pyro-electrolytic conductor connected or adapted to be connected in an electric circuit, of arcing-points for heating the conductor, and means for automatically separating the points to such an extent when the conductor has become heated that the arc is thereby broken.

19. In an electric lamp, the combination with a pyro-electrolytic conductor connected or adapted to be connected in an electric circuit, of arcing-points for heating the conductor and means for breaking the are when the conductor has been heated.

20. In an electric lamp, the combination with arcing-electrodes, of an illuminant in proximity thereto, and a magnetic field adapted to deflect and direct against the said illuminant, the arc formed between said electrodes.

In witness whereof I have hereunto set my hand this 4th day of May, 1899.

ELIHU THOMSON.

Witnesses:

DUGALD MOKILLOP, HENRY O. WESTENDARP. 

